1. Field of the Invention
This invention relates to means for measuring a quantity of asphalt ingredient in an asphalt compound and more particularly to means for checking the amount of asphalt ingredient mixed into an asphalt compound within predetermined limits.
2. Prior Art
Generally to produce asphalt compound, uniform crushed stone and asphalt ingredient are mixed together under heat within a fixed mixture ratio (which is standardized) in proportion to the grades. However, in a practical sense the standard value for the fixed mixture ratio only exists after the asphalt ingredient and the crushed stone are mixed together. Therefore, in the prior art apparatus it has been almost impossible to uniformally control the fixed mixture ratio between the asphalt ingredient and crushed stone in the asphalt compound. It has been suggested that a feedback control system could overcome this difficulty but such a system has not been invented or implemented as yet. Additionally, in the prior art apparatuses when the crushed old asphalt compound is reused instead of crushed stone, it is required to measure the amount of asphalt ingredient which is contained in the old asphalt compound prior to introducing it into the apparatus from mixing the asphalt ingredients and the old asphalt compound. Such additional work adds to the steps of manufacture ashpalt compound and increases the cost.